1. Field of the Invention
The invention relates to a fixation element for an implantable microphone which, with a cylindrical housing part provided with an acoustic inlet membrane, can be inserted into a hole which crosses the rear bony wall of the auditory canal and which, for example, can form a component of a partially or fully implantable hearing aid.
2. Description of Related Art
One embodiment of a microphone of the aforementioned type is the subject of commonly owned U.S. patent application Ser. No. 08/816,633, filed Mar. 13, 1997, and is detailed in the article "An implantable microphone for electronic hearing implants" by H. Leysieffer et al., HNO 45: 816-827 (October 1997). It is known from this article that the microphone housing can be mechanically fixed in the mastoid using bone cement. However, fixing with cement engenders a number of problems. Under certain circumstances the bone cement can trigger undesirable side effects at the implantation site. Due to the restricted space conditions and unfavorable visual conditions, handling at the implantation site is difficult. Bone cement can also unwantedly reach locations where it is disruptive. Subsequent correction of the microphone location in the hole of the wall of the auditory canal is essentially precluded. Clinical experiments show that this is a problem due to the small thickness of the bony wall of the auditory canal. In addition, screws in the region of this implantation site are often felt to be painful even long after surgery.